OptimizelyUserContext for the Swift SDK

public class OptimizelyUserContext {
  public var userId: String
  public var attributes: [String: Any?]
  
  public init(optimizely: OptimizelyClient,
              userId: String, 
              attributes: [String: Any]? = nil)
  
  // set an attribute for the user
  public func setAttribute(key: String, value: Any) -> Bool    
  
  // make a decision about which flag variation the user buckets into for the flag key 
  public func decide(key: String, 
                     options: [OptimizelyDecideOption]? = nil) -> OptimizelyDecision
  
  // make decisions about which flag variations the user buckets into for flag keys
  public func decide(keys: [String],                
                    options: [OptimizelyDecideOption]? = nil) -> [String: OptimizelyDecision]
  
  // make decisions about which flag variations the user buckets into for all flags
  public func decideAll(options: [OptimizelyDecideOption]? = nil) -> [String: OptimizelyDecision]
  
  // track user event
  public func trackEvent(eventKey: String, eventTags:  [String: Any]? = nil)
  
  // OptimizelyDecisionContext
  public struct OptimizelyDecisionContext {
    public let flagKey: String
    public let ruleKey: String?
  }
  
  // OptimizelyForcedDecision
  public struct OptimizelyForcedDecision {
    public let variationKey:String
  }
  
  // sets a forced decision (variationKey) for a given decision context (flagKey and optional ruleKey)
  public func setForcedDecision(context: OptimizelyDecisionContext, 
                                decision: OptimizelyForcedDecision) -> Bool
  
  // returns the forced decision (variationKey) for a given decision context (flagKey and optional ruleKey)
  public func getForcedDecision(context: OptimizelyDecisionContext) -> OptimizelyForcedDecision?

  // removes the forced decision (variationKey) for a given decision context (flagKey and optional ruleKey)
  public func removeForcedDecision(context: OptimizelyDecisionContext) -> Bool

  // removes all the forced decisions (variationKeys) for the user context
  public func removeAllForcedDecisions() -> Bool

  //
  // The following methods require Real-Time Segments for Feature Experimentation. 
  // See note below code sample. 
  //

  // An array of segment names that the user is qualified for. 
  // The result of **fetchQualifiedSegments()** will be saved here. 
  // Can be nil if not properly updated with fetchQualifiedSegments(). 
  // 
  //  You can read and write directly to the qualified segments array. 
  //  This allows for bypassing the remote fetching process from ODP 
  //  or for utilizing your own fetching service.   
  public var qualifiedSegments: [String]? 

  // Fetch all qualified segments for the user context. 
  //
  // The segments fetched will be saved in **qualifiedSegments** and can be accessed any time.
  // On failure, **qualifiedSegments** will be nil and one of these errors will be returned:
  // - OptimizelyError.invalidSegmentIdentifier
  // - OptimizelyError.fetchSegmentsFailed(String)
  //
  // - Parameters:
  //   - options: A set of options for fetching qualified segments (optional).
  //   - completionHandler: A completion handler to be called with the fetch result. 
  //     On success, it will pass a non-nil segments array (can be empty) with a nil error. 
  //     On failure, it will pass a non-nil error with a nil segments array.
  public func fetchQualifiedSegments(options: [OptimizelySegmentOption] = [],
                                     completionHandler: @escaping ([String]?, OptimizelyError?) -> Void)


  //  Check is the user qualified for the given segment. 
  // - Parameter segment: the segment name to check qualification for.
  // - Returns: true if qualified.
  public func isQualifiedFor(segment: String) -> Bool
}